Liquid-fuel burner



Dec. 11, 19 28.

c. H. BALMAT LIQUID FUEL BURNER Fil ed Margh 22, 1926 @4102 um, J.

Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

CECIL H. BALMAT, OF SAN FRANCISCO, CALIFORNIA,

ASSIGNOR, BY MESNE ASSIGN- MENTS, '10 STANDARD OIL COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALI- FORN IA, A CORPORATION OF DELAWARE. 1

' LIQUID-FUEL BURNER.

Application filed March 22, 1926. Serial No. 96,528.

This invention relates to an oil burner for burning fuel oils, especially heavy fuel oils. In order to burn such oils satisfactorily it is necessary to effect a suitable'atomization of 6 the fuel, to provide the correct quantity ofair, and to maintain the proper temperature during combustion. The burners which are used in industrial plants for burning heavy oils are usually either of a type in which 10 steam, or sometimes air, under high pressure, is utilized to atomize the oil. type of burner is employed in which the oil is broken up by mechanical means, either by being forced to issue from a small orifice or from the periphery of arapidly revolving cup. In domestic installations steam under high pressure is not available; neither is compressed air, and furthermore burners using these'means for atomization are noisy in operation and require exact control, preferably .by an expert. Burners using mechanical means ifor effecting the pulverization of the fuel are in general not very flexible under domestic conditions-that is to say, they are not readily adaptablefor being changed from an adjustment for a small fire to an adjustmentfor producing a large fire. Furthermore, they require considerable cleaning. Those burners which utilize pressure alone for the atomization ofthe oil require high pressure pumps, and in small sizes, such as would be suitable for domestic use, the orifices are necessarily so small as to become very easily stopped mi. y

The general 0 ject of this invention is to overcome these dificulties and to produce a burner of simple construction which can be readily used for developing a small fire or a lar e fire; also to provide a construction in lo WhlCll the fuel oil will be adequately heated to promote its atomization, but in which the fuel is sufficiently protected from the furnace heat to prevent its reduction to a tarry or carbonaceous residue. A further object of the invention is to rovide a burner of this type in which the uel ducts are relatively large and placed so that they can be readily cleaned. A further object is to provide an oil burner having a special construction at its 0 tip which develops a relatively large atomizing area or zone and which will bring the air blast into intimate contact with the oil.

A further object of the invention is to im- Another pear hereinafter.

r The invention consistsin the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an eflicient liquid fuel burner.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended-claims.

In the drawing:

Figure 1 is a bottom plan of a burner embodylng my invention.

Figure 2 is a longitudinal vertical section throughthe burner in its upright position.

Figure 3 is a longitudinal section through the inner nozzle which carries the liquid burner.

Figure 4: is 'a section taken about on the line 44 of Fig. 3, and further illustrating details of the inventio Figure 5 is a section further illustrating. details of the invention.

Figure dis a side elevation of the tip of the fuel nozzle with its outer shell removed,

.and particularly illustrating details of its inner shell.

In practicin my invention I provide an outer nozzle 1 or carryin an air blast which may be admitted throug an opening 2 at the back end of'the nozzle where a flange 3 is provided for attachment to the blast pipe. This outer nozzle has a mouth 4 at its for Ward or inner end at which the air blast is emitted and at this point the outer nozzlemay be provided with a tapered tip 5. t,

Within the outer nozzle I provide an inner nozzle 6 for conducting the liquid fuel to the vicinity of the mouth 4. At its rear end this inner nozzle has an enlarged collar '7 which may fit into a bore 8 at the rear end of the outer nozzle, at which point it may be secured by a set screw'9= N ear its inner end the outer nozzle is provided with a transverse bar 10, the middle point of Which is formed into a hub 11 with a central opening 12 which receives a reduced neck 13 formed near the inner end of the nozzle. Beyond this hub 11, the inner nozzle is formed with a tip 14 which is of reducedsize and preferably substantially wedge shape,

as illustrated in Figs. I

fuel cap orfuel tip 17. This cap is constructed in the form of an annular shell with a double wall so that a narrow annular space 18 is formed around the longitudinal axis of the tip. This annular space is preferably so narrow that it will be capillary in its action. It

is supplied with fuel throu h one of the annular walls, and this fuel nds egress at the annular line forming the extreme tip of the fuel nozzle.

The cap or fuel tip 17 preferably consists of an inner shell 19 which seats over the wedge-shape ti 14 of the inner nozzle and may be attache to the same by a cross pin 20 (see Figs. 3, 4 and 6). The tip 14is provided with a duct 21. communicating with the duct 15 and terminating in a duct 22 of reduced diameter, which extends well up into the extremity of the tip 14, at which point it communicates with a transverse duct 23 in the end of the. tip that emerges at the side edges of the tip (see Fig. 4). The inner shell 19 has two diametrically opposite openings 24 which communicate with the ends of this transverse duct 23. The tip or cap 17 also includes an outer shell 25 which is removably attached over the inner shell concentrically so as to produce the annular oil space 18. For this purpose, I prefer to provide the outer surface of the inner shell 19 with interrupted screw-threads 26 which cooperate with corresponding interrupted screw-threads formed on the inner face of.

the outer shell 25. a

I prefer to construct'these parts so that the inner diameter of the inner shell is considerably greater than the thickness of the tip 14 so that an air passa e 27 is formed through the bore of the tip 1?. By reason of this construction, when the air blast passes through the mouthxt, a considerable quantlty of air passes through the interior of the fuel tip l'? and this produces a very efiicient atomization of the fuel and gives a relatively large zone of atomization.

The quantity of liquid fuel admitted may be controlled by valves, not illustrated, which are in the fuel pipe connection, which is attached-at the coupling 16.

In us n this burner in a furnace, it should beset in t e wall of the furnace as indicated by the dotted lines 28 in Fig. 2. Of course the furnace wall becomes heated from the flame within the furnace and the interior of the burner maintains a fairly high temperature, sufiicient, at least, to enable the heavy fuel to flow freely through-the inner nozzle. However, by reason of the fact that the air blast surrounds the inner nozzle, it becomes impossible for the inner nozzle to become overheated under ordinary working conditions though the fuel will be adequately heated for atomization but without the production of tarry or carbonaceous residue in the fuel nozzle.

If desired, the outer-nozzle may be provided with a gas duct 29 extending longitudinally in one of its walls, the mouth 80 of which is located near the tip' of the burner. This enables a gas pilot light to be employed to light the burner when the fuel and air blast are turned on. It will be evident that the ducts for the fuel through *the inner nozzle are relatively large so that they do not tend to clog up, and it will also be evident that by removing the outer shell 25 of the fuel tip, the annular space 18 can be readily cleaned and also the transverse duct 23.

Although this duct 23 delivers the fuel to the rear of the threads 26, it will be evident that by reason of the fact that this thread is interrupted, the gap 31 through the thread Which is located opposite to the ends of the duct 23 enables the oilto move forwardly in the capillary space 18. I

It is understood that the embodiment of the invention described herein is only one of the man embodiments this invention may take,'an I do not wish to be limited in the practice of the invention, nor in the claims, to the particular embodiment set forth.

What I claim is:

1. In an oil burner, the combination of an outer nozzle for conducting an air blast and which the air blast is delivered, an inner nozzle carried within the outer nozzle and having a fuel duct for the oil, said inner nozzle having a wedge shaped tip with a transverse fuel duct, for taking the fuel from the first named fuel duct, a delivery cap consisting of an inner-annular shell encircling and attached to the said tip in said mouth, and an outer. annular shell secured over the inner shell and co-operating with the same to form a substantially capillary space communicating with the transverseduct.

2. In an oil burner, the combination of an outer nozzle for conducting an air blast having a mouth at its forward end through which the air blast is delivered, an inner nozzle carried within the outer nozzle having a fuel duct for the oil and having a wedgesaid delivery cap including an outer annular shell secured over the inner shell and coinner nozzle for the oil having a wedge,

shaped tip with a fuel duct extending into ,the same, an annular shell encircling the tip and attached to the side edges of the tip so that there is an air passage on each side between the flat sides of the tip and the wall of the shell, said tip havin duct emerging at the side e ges of the tip communicating with the first named duct and having a port passing through the wall of said shell, and an outer annular shell detachably secured to the first named annular shell and co-operating therewith to form an annularsubstantially capillary space receiving the oil through the port.

4. In an oil burner, the combination of an outer nozzle for conducting an air blast, having a mouth at its outer end through which the air blast is delivered, an inner nozzle carried within the outer nozzle having a wedge shaped tip with a fuel duct for the oil passing into the said tip, an annular shell secured to the side edges of said tip so that there is an air passage on each side of the tip between the tip and the wall of the said a transverse shell, said tip having a transverse duct emerging on the side edges of the tip leading the oil through the wall of the said shell, and an outer shell detachably secured to the inner shell and co-operating therewith to form an annular substantially capillary space for the oil. 5

5. In an oil burner, the combination of an inner fuel nozzle with a wedge shaped tip having a longitudinally disposed fuel duct therein, an inner tubular shell encircling the wedge shaped tip seating against the side edges of the wedge shaped tip and secured to the tip, said burner having a transverse for fuel duct in said tip communicating withthe first named fuel duct, emerging at said side edges and passing through the wall of the said tubular inner shell, and an outer shell of tubular form received over said inner shell with means for removably securing the same to the inner shell, said inner shell cooperating with the wedge shaped tip to form an air passage through the inner shell on each side of the wedge shaped tip, saidtubular shells cooperatin to form an annular capillary space for the uel.

Signed at San Francisco, California, this 1st day of March, 1926.

CECIL H. BALMAT. 

